Fuel valve control system
US4806095A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 21, 1988 |
| Grant date | Feb 21, 1989 |
| Priority date | — |
| Expiry date | Jan 21, 2008 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T137/1407
- WIPO fieldThermal processes and apparatus
- WIPO sectorMechanical engineering
Abstract
A fail safe gas shut off system is provided for a gas appliance. Two normally closed valve stages are provided in series, with each stage operated by a bidirectional solenoid armature. When the armature moves in one direction, the first stage of the valve is opened to supply gas to a pilot burner and to the second stage of the valve. When the pilot flame heats an emissive element to produce sufficient radiation, a photovoltaic device illuminated by the emissive element produces current for an electromagnet which latches the first stage of the valve in its open position. The armature can then move in the opposite direction and open the second stage of the valve to supply gas to the main burner. In the event of pilot flame failure, the emissive element darkens, and current from the photovoltaic device ends. The electromagnet releases the first stage of the valve which is biased closed and cuts off gas flow to both the pilot and main burners.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.